New Zealand Journal of Geology and Geophysics abstracts

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Volcanic tremor and activity at White Island, New Zealand, July-September 1991

STEVEN SHERBURN
BRADLEY J. SCOTT

Institute of Geological & Nuclear Sciences
Wairakei Research Centre
Private Bag 2000
Taupo, New Zealand

A. W. HURST

Institute of Geological & Nuclear Sciences
Kelburn Centre
P.O. Box 1320
Wellington, New Zealand

Abstract  A short, intense sequence of volcano-tectonic earthquakes preceded a period of strong volcanic tremor at White Island volcano, New Zealand, in July-September 1991. The tremor was initially harmonic with clear higher harmonics, but after 3 days was gradually replaced by broadband non-harmonic tremor. Good examples of both harmonic and non-harmonic tremor were recorded. Shock waves were observed in the eruption column of May 91 vent from early August, coinciding with the period of non-harmonic tremor. The harmonic tremor is interpreted to have been due to a standing wave vibration in vesicular magma in the conduit beneath May 91 Vent, and the non-harmonic tremor to open-vent degassing activity near the top of the vent.

Keywords  volcanic tremor; White Island; volcano seismicity; eruptive activity

New Zealand Journal of Geology and Geophysics, 1996, Vol. 39: 329-332

0028-8306/96/3902-0329 $2.50/0 (c) The Royal Society of New Zealand 1996

PDF file of entire paper: medium quality (1064K); (scanned from paper original: notes about this process)

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